抄録
Electrical steel sheet is using for interior permanent magnet (IPM) motor of hybrid electric vehicle (HEV) and electric vehicle (EV). In order to raise allowance rotating speed of IPM motor to realize high efficiency, it is necessary to improve yield stress of the electrical steel sheet by partially strengthening method such as peening, as the high-strength electrical steel sheet enhanced by rolling has low conversion efficiency because of high iron loss. A peening method using cavitation impact named as "cavitation peening (CP)" can improve the fatigue strength of metallic materials by introducing compressive residual stress. CP can peen the surface even through deep narrow region, as the bubbles can reach these parts and collapse where peening is required such as stress concentration area. In the present paper, the electrical steel sheet was peened by CP and the tensile test was conducted in order to demonstrate that improvement of yield stress of the electrical steel sheet for IPM motor by CP.
